Welded joint



Patented Aug. 12, 1947 UNITED STATE S PATENT;

,OFFICE WELDED JOINT 7,1937, I described a method and apparatus for` making an electric resistance surface lweld J'oint and in my Patent No. 2,183,563, issued December 19, 1939, I described and claimedthatn joint. In my copending application Ser. No. 568,259 filed December 15, 1944, nowPatent No; 2,417,075, issued March 11, 1.947, I have described and claimed new apparatus for carrying out the method of Patent No. 2,091,982 and for making not only the joints of that patent and of Patent No. 2,183,563 but also joints which are herein disclosed and claimed.

The joint of the present invention is an improvement of the joint described in my aforesaid patents and is characterized by possessing the advantageous features of those previously described joints and additional desirable features presently to be described.

In the drawings accompanying and forming a part of this specification,

Figure 1 is a side elevational view of a joint of the present invention connecting the end of one tube to the side of another tube;

Figure 1a is an end elevational view of the joint of Fig. 1;

Figure 2 is an enlarged sectional view taken on line 2-2 of Fig. 1a; and,

Figure 3 is an enlarged sectional view taken on line 3 3 of Fig. 1.l

In Fig. 1 the outer, curved side surface of tube I is joined to the end surface of tube 2 by a illleted electric resistance surface weld 3. As will be noted from this figure and also Figs. 2 and 3, the weld metal extends beyond the outer surface of tube 2 and fills the angular space between tubes I and 2 where it has a curved or fllleted outer surface 4. This llleted surface gives a finished appearance to the joint and makes flnishing operations, such as polishing, painting and the like, easy to perform.

Figs. 2 and 3 show an important feature of this invention, viz.: that the depth of penetration of welding heat into the end of the tube 2 is less than the radial thickness of that tube. It -Will be understood that, since Fig. 3 which is taken on v Kenneth V. Hart, clevelandoho y I, Application December 15, 1914, serial No. 568,258

1 claim. (ci. zas- 111).

.l I, the sheet of drawing should be turned counterl, clockwise about-45, Awhen Fig. 3 is being viewed to place itin a more nearly -true position. The

Wall Oftube. 2 is lgage or .062" While the depth of heatlpenetrationin Fig. 2 ranges fromlabout .05" to about .06.A In. Fig. 3 the truel depth of heat penetration is about .06" as is indicated on the :inner side ofl tube- 2, lthe greater apparent depth along the outer side Ibeing'due to the combinedi heating eiect of the current on the initial narrow`contact area of the tube end and of the thusv heated metal 4which is forced outinto the wedge shaped recessbetween the two tubes. The metal of tube 2 within the heated portion defined by the heat linev and the-tube endhas been up- .set and somewhat thickened by the welding presesure.-

The heat supplied during thegweldingA operation altered `the metallographic structure-ofv the metaiof .tube 2 to a surprisinglyV slight extent. Even at points closely adjacent to the weld the metal of tube 2 'was vaifected only to a slight extent` as was indicated by a small amount of carbon precipitation at the grain boundaries. There was practically no noticeable enlargement of the grains of the tube. At points morefand more remote from the weld the amount cf carbon precipitation gradually decreased until it ceased at the heat line or end of heat penetration. 'I'he metallographic structure of the metal of tubes I and 2, even closely adjacent to the weld,4 is not altered in any practical sense of the Word during Welding and neither the weld metal nor tubes I and 2 is oxidized by the welding heat to a material extent. y y

Figs. 2 and 3 also show another important feature of welds embodying the present invention. The length of the weld metal, measured radially of tube 2, is thicker than the wall of that tube, preferably at least 50% thicker. The radial thickness of the Wall of tube 2 of thesevfigures is .062 while the radial length of the Welds of s Figs. 2 and 3 is .10" and .11" respectively.

tube 2.

line 3-3 of Fig. 1, shows part oi' the side of tube 66 Welds embodying the three foregoing important features are considerably stronger than the body metal of tube 2 and serve to absorb stresses. shocks and loads transmitted to it by either of the welded members kand 'to distribute those forces to the other welded member.

In making-welds embodyingfthe present invention the end oi tube 2'1s preferably `.shaped after.` the manner shown in myabove mentioned ,.patl. ents to conform Eto the opposed tube or other` member which .is to be `welded thereto. "This l shaping yinvolves providing on 'the end of tube r2 a narrow, radially rShort or, substantially line, `contact thruout the circumferencewof the tube with fthe opposed-metal member .and a 'beveled surface which vforms -with the opposed .member an includedsmall, acute angle.

The apparatus for and methodof makingrwelds of the `present invention between members shaped as just described isset out Ain considerable detail in my copending application Ser. No. v

568,259, iiled December .15, 1944, now Patent No. 2,417,075, issued March -11, 1947. Briey stated,

that apparatus .includes @an `electrode whichcan supply a heavy-current for-avery' brief interval of time, such `asthat equivalent -tofthetimeo'f a half cycle oraifew cycles of sixty-cycle alternating current, to the engaged portions of the two articles, thereby almostjinstantaneously gener- 3 ating very high heat in the radially short coni tact area which has great resistance and heating. 1 kthe metal `behind thatmetalto a deformable, ex-

trudable or forgeable condition. That apparatus .also .includes `mechanism for advancing "the .said

ant formation ora vconcav'o-convex weld line I c l which is concave in the opposed member` convex at the tube end..

It will be understood that joints of thev present invention may be made not only between the end of a tube and the side of another tube. but lalso between the end of a' tube nd the side of -another'mem'ber which may bea fiat plate or other non-tubular member.

Having .thus described my yinvention so that others skilledin the art may be able to understand and practice the same, I state that what I desire to secure by Letters Patent is denedin what is claimed. Y

Whatis claimed is:

v A metal structure comprising a tubular metal member, an opposed metal member and 'a resistance surface Weld uniting an end of said tubular member to a side of said opposed member, said electrode under'hignpressurefas the metal ofthe i til-berend softens. 'fInthis `manner the highly f heated weldable'metalofthe tube-end is spread laterally between lthe surfaces of 'the tufbe end,

and the opposed fmem'ber until it has-a radial length at least -fty per cent vgreater than the thickness vofzthe wall .of the tube, and the tube end is caused'to penetrate'finto theopposed mem- The following references areof ber to'the extentofffromabout.15%1toabout'25% of the wall thickness of thetube end with resultweld .having a radial thickness at least fifty per cent greater than the Wall thickness of the tubular member, the end 'surface'of said tubular member penetrating into said opposedmember to be- -tween about 15%. and about 215% of the wall thickness of the tubular member, said penetration being incident to Vpressure applied during the welding process the depth of heat penetration in the tubularmember. as evidenced by carbon precipitation, being less than 'the wall thickness of the tubular member.

KENNETH V.

REFERENCES CITED file of this patent: u y

STATES P ATENTS Number Name Date 1,992,960 Mller Q -.Q Mal'. 5, 1935 1,924,121 A118229, 1933 Jasper record in the 

